semaphore

A visual signaling apparatus with flags, lights, or mechanically moving arms, as one used on a railroad.

A visual system for sending information by means of two flags that are held one in each hand, using an alphabetic code based on the position of the signaler's arms.

tr. & intr.v.

sem·a·phored, sem·a·phor·ing, sem·a·phores

To send (a message) or to signal by semaphore.

Origin of semaphore

Greek s&emacron;ma, sign + –phore.

Related Forms:

sem′a·phor′ic

adjective

sem′a·phor′i·cal·ly

adverb

semaphore

top: railroad signal

bottom: flag signal system

semaphore

semaphore

Noun

(plural semaphores)

Any visual signaling system with flags, lights, or mechanically moving arms.

A visual system for transmitting information by means of two flags that are held one in each hand, using an alphabetic and numeric code based on the position of the signaler’s arms.

(computing) A bit, token, fragment of code, or some other mechanism which is used to restrict access to a shared function or device to a single process at a time, or to synchronize and coordinate events in different processes.

semaphore - Computer Definition

(1) A hardware or software flag used to indicate the status of some activity. See flag.

(2) A shared space for interprocess communications (IPC) controlled by "wake up" and "sleep" commands. The source process fills a queue and goes to sleep until the destination process uses the data and tells the source process to wake up. See IPC.